My car was running and in park and shut off. Now it won't start at all. It doesn't turn over and I know it's not the battery. Any ideas?

Does it have an immobiliser? If so it could be a problem with that. I remember years ago breaking my car key and the immobliser chip fell out and the car wouldn't start. I am having problems wit my starter motor at the moment, it doesn't always work (getting it sorted tomorrow lol) so it might be that. I am no mechanic though!

See if this helps:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563-3.html#post235560